Arlon Silicone Technologies Glossary

The American National Standards Institute (ANSI) is a private, non-profit organization (501(c)3) that administers and coordinates the U.S. voluntary standardization and conformity assessment system.

ASQC

The American Society for Quality Control (ASQC) is the world's leading authority on quality. With more than 100,000 individual and organizational members, this professional association advances learning, quality improvement, and knowledge exchange to improve business results, and to create better workplaces and communities worldwide.

BS EN

British European Standards Specification maintained by BSI. BSI British Standards is the National Standards Body of the UK and develops standards and standardization solutions to meet the needs of business and society. They work with government, businesses and consumers to represent UK interests and facilitate the production of British, European and international standards.

Calendaring

Finishing process by which paper, plastics, rubber, or textiles are pressed into sheets and smoothed, glazed, polished, or given a moiré or embossed surface. The material is passed through a series of rollers; the resulting surface depends on the pressure exerted by the rollers, on their temperature, composition, and surface designs, and on the type of coating or glaze previously applied to the material to be calendared.

Chemical Resistance

Ability to resist the deteriorating effects of exposure to various chemicals under specified conditions.

Coefficient of Thermal Expansion (CTE)

A measure of how much a material will lengthen (or shorten upon cooling) based on its original length and the temperature difference it is exposed to. It becomes important when dimensions are critical or when two different materials with different CTE's are attached to each other, such as an unfilled thermoplastic and steel. Stress induced by this difference can become considerable. Usually expressed in terms of length/length/unit temperature.

Composite

An homogeneous material created by the synthetic assembly of two or more materials (selected reinforcing elements and compatible matrix resin) to obtain specific characteristics and properties.

Compression Set

The amount by which a rubber specimen fails to return to its original shape after release of compression load. The numerical value is that percentage of the amount compressed that does not return.

Dielectric Srength (Breakdown)

A measure of the resistance of a dielectric to electrical breakdown under the influence of strong electric fields; usually expressed in volts per meter. The dielectric strength of dry air at sea level pressures is about 3 000 000 V*m^-1.

Dispersion Coating

Process in which silicone rubber is dispersed in a liquid carrier and applied to a fabric. The dispersion penetrates and coats the fabric or substrate forming a rubber coating.

Durometer

A device used to measure the hardness of rubber. The term also applies to the numerical unit of measurement so obtained, and is used to denote the degree of hardness, higher numbers denote greater hardness.

Elastomer

Any synthetic or natural material with resilience or memory sufficient to return to its original shape after major or minor distortion.

Extrusion

A manufacturing process that utilizes a softened billet of material which is forced through a shape (or die) to allow for a continuous form.

Hardness

In materials science, hardness is the characteristic of a solid material expressing its resistance to permanent deformation.

Ionic Migration

A way of conducting electricity where you have charged particles moving through a matrix of some sort.

A process by which different materials are layered and then bonded together using adhesion.

Lap Shear Strength

A measure of the bond strength between an adhesive or encapsulant and a substrate. The test involves pulling an overlapped joint in the same director as the bondline. The overlapped area is usually one inch by one inch. Often expressed in pounds per square inch (psi).

Modulus of Elasticity

The proportional constant between stress and strain for material with linear elastic behavior: calculated as stress divided by strain. Modulus of elasticity can be interpreted as the slope of the stress-strain graph. It is usually denoted as E, sometimes known as Young's Modulus Y, or E-Modulus.

Modulus of Rigidity

Rate of change of strain as a function of stress in a specimen subjected to shear or torsion loading. It is the modulus of elasticity determined in a torsion test. Alternate terms are modulus of elasticity in torsion and modulus of elasticity in shear. Apparent modulus of rigidity is a measure of the stiffness of plastics measured in a torsion test (ASTM D-1043). It is "apparent" because the specimen may be deflected past its proportional limit and the value calculated may not represent the true modulus of elasticity within the elastic limit of the material.

Molding

The process of manufacturing by shaping pliable raw material using a rigid frame or model called a mold.

Outgassing

Outgassing is a problem encountered in high-vacuum environments and applications. For example, NASA maintains a list of low-outgassing materials to be used for spacecraft, as outgassing can cause deposits on optical elements, thermal radiators, or solar cells. Materials not normally considered absorbent can release enough light molecules to interfere with industrial or scientific processes.

Polymer

Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeated linked units, each a relatively light and simple molecule.

Rheology

The science of deformation and flow of matter. In practice, rheology is principally concerned with extending the "classical" disciplines of elasticity and Newtonian fluid mechanics to more complicated materials. Flows of elastic solutions and of those containing long-chain polymers, including coatings, as well as flows in extruders, molds, and other processing equipment, dominate rheology today.

RoHS

The Restriction of Hazardous Substances Directive (ROHS) became European Law in February 2003. Together with the Directive on Waste Electronic and Electric Equipment (WEEE) which is setting collection, recycling and recovery targets for all types of electrical goods it is part of a legislative initiative to solve the problem of huge amounts of toxic e-waste.

Shear Modulus

In materials science, shear modulus S, sometimes referred to as the modulus of rigidity, is defined as the ratio of shear stress to the shear strain in a linear elastic material.

Shore A

Hardness test in accordance with Shore A (DIN 53505) for hard rubber. A scale used for the measurement of rubber hardness.

Silicone

Any of a large class of siloxanes that are unusually stable over a wide range of temperatures; used in lubricants, adhesives, coatings, synthetic rubber and electrical insulation.

Substrate

A material upon the surface of which an adhesive-containing substance is spread for any purpose, such as bonding or coating.

Tensile (Break) Strength

Ultimate strength of a material subjected to tensile loading. It is the maximum stress developed in a material in a tensile test before failure.

Tensile Elongation

The amount of stretch a sample experiences during tensile strain. ASTM D-638.

Thermal Conductivity

The ability of a material to conduct heat; the physical constant for quantity of heat that passes through a unit of volume of a substance in a unit of time when the difference in temperature of two opposite faces is 1°.

Materials in a sizing or a resin formulation that can be vaporized at room or slightly elevated temperature.

Volume Resistivity

The electrical resistance between the opposite faces of a solid volume of insulating material. It is measured under prescribed conditions using a direct current potential after a specified time of electrification. Commonly expressed in ohm-cm.

Young's Modulus

Young's Modulus, or Modulus of Elasticity, is the proportional constant between stress and strain for material with linear elastic behavior: calculated as stress divided by strain. Modulus of elasticity can be interpreted as the slope of the stress-strain graph. It is usually denoted as E, Y, or E-Modulus.